DUBLIN — Sinn Féin has scaled new electoral heights in Northern Ireland. They can thank the Stormont-wrecking antics of their sworn enemies, the Democratic Unionist Party, for making it possible.

The Irish republicans had been tipped to finish a strong first place in Northern Ireland’s council elections last Thursday, overtaking Jeffrey Donaldson’s DUP along the way. But even Sinn Fein’s wildest hopes were eclipsed as the weekend’s results built to a crescendo over a marathon two-day count.

When final results were declared in Belfast City Hall after midnight Saturday, Sinn Féin had won 144 seats, a 39-seat gain that more than doubled expectations. Its 30.9 percent share of the vote marked a historic high, two points better even than last year’s poll-topping Northern Ireland Assembly election — a performance that should have propelled the party’s regional leader, Michelle O’Neill, into the first minister’s chair for the first time.

But O’Neill has been denied the chance to lead a cross-community executive, as the Good Friday peace accord intended, because the Democratic Unionists — used to finishing first — have spent the past year blocking the formation of any government at Stormont. The current rules of power-sharing require both Sinn Féin and the DUP to participate.

According to analysts and other party leaders, the DUP’s obstructionist tactics may have galvanized support with unionist die-hards — but also triggered waves of new support for their traditional enemies from voters sick of the deadlock.

“Jeffrey Donaldson has become the greatest recruiting sergeant possible for republicans. The longer Michelle O’Neill is blocked from becoming first minister, the more voters are driven into the arms of her party,” wrote Suzanne Breen, political editor of the Belfast Telegraph.

Social Democratic and Labour Party leader Colum Eastwood, who competes with Sinn Féin in Irish nationalist areas, said his own moderate party’s grassroots had switched to Sinn Féin in unprecedented numbers because the DUP had exhausted their patience.

“They’re very annoyed that Michelle O’Neill hasn’t been able to become first minister,” said Eastwood, whose party — one of the architects of the Good Friday breakthrough a quarter-century ago — suffered heavy losses amid the Sinn Féin-DUP showdown.

“They want politicians to get back to work and deal with the issues besetting our community,” Eastwood said. “Now it’s over to the DUP to get on with it.”

Still waiting

When or whether the DUP actually does so remains far from certain, given that its own vote held up well at Thursday’s election.

Donaldson and other senior DUP figures have spent the past three months picking holes in the British government’s Windsor Framework, the successor post-Brexit trade deal for Northern Ireland designed to reduce — but not eliminate — EU-required checks on goods arriving from the rest of the United Kingdom. Unionists argue such checks effectively place Northern Ireland partly outside the U.K., and on a slippery slope toward a united Ireland, Sinn Féin’s ultimate goal.

U.K. Prime Minister Rishi Sunak had hoped the Windsor Framework compromise package would have persuaded the DUP to resume cooperation at Stormont with a strengthened Sinn Féin.

But Donaldson told reporters at Belfast City Hall that his party’s resilient performance — it won 122 of the 462 seats on Northern Ireland’s 11 councils, the exact same total as in the 2019 election — showed most unionists would rather have no Stormont than accept “barriers to trade between Northern Ireland and Great Britain.”

“The DUP have polled strongly despite everything that has been thrown at us,” said Donaldson, who now wants Westminster to pass unspecified legislation reinforcing Northern Ireland’s constitutional ties to Britain. “The U.K. government must move to ensure that our place in the United Kingdom is not only respected, but protected in law. The mandate we’ve been given reinforces that message.”

His immediate predecessor as DUP leader, Edwin Poots, said while others expected the party to end its Stormont sabotage now that the election was out of the way, such a move remains unlikely unless the U.K. government finds extra support for Stormont’s ailing finances.

“We’re ready to go back but we need to get more than what’s currently on the table,” Poots said. “If we went back into the assembly and executive in the morning, with this budget, the first task of every minister would be to implement cuts. It’s imperative that we get a package to ensure this will not be the case.”

O’Neill, who spent much of the weekend joining in jubilant scenes with Sinn Féin activists, expressed exasperation that the DUP might string others along indefinitely for many months longer.

“I am not accepting the autumn as a timeframe for a restored executive, as a lot of people are suggesting. There shouldn’t be any more delays. Let’s do it Monday morning,” she said.

Joining O’Neill in Belfast was Sinn Féin’s overall leader, Mary Lou McDonald, a Dubliner whose eye remains on a bigger prize: leading a government in the neighboring Republic of Ireland for the first time.

Sinn Féin, the only party contesting elections in both parts of Ireland, wants as part of its Irish unity strategy to gain the reins of power in both jurisdictions simultaneously. For decades a fanciful dream — and a unionist nightmare — this scenario has become a probability.

The party’s growth to become the top party in Northern Ireland is matched south of the border by McDonald’s successful efforts to build Sinn Féin into the dominant opposition party in Dáil Éireann, Ireland’s parliament. It has topped every opinion poll for years and looks likely to win the next general election, which must happen by 2025 but could come sooner.

As McDonald and O’Neill together ascended the steps of Belfast City Hall, Sinn Féin activists cheered their party’s rising expectations of gaining power in both the Dáil and Stormont, with McDonald as prime minister in Dublin and O’Neill as first minister in Belfast — if the DUP ever relents.